The present invention relates to the use of organic light emitting diodes for area illumination.
Solid-state lighting devices made of light emitting diodes are increasingly useful for applications requiring robustness and long-life. For example, solid-state LEDs are found today in automotive applications. These devices are typically formed by combining multiple, small LED devices providing a point light source into a single module together with glass lenses suitably designed to control the light as is desired for a particular application (see, for example WO99/57945, published Nov. 11, 1999). These multiple devices are expensive and complex to manufacture and integrate into single area illumination devices. Moreover, LED devices provide point sources of light that are not preferred for area illumination.
It is known to manufacture an OLED light source or display device on a flexible substrate. See for example EP0949850 A1, published Oct. 13, 1999 that shows a substrate comprising a laminated substrate of plastic and glass. The manufacture of the OLED device on a flexible substrate facilitates continuous manufacture, wherein the substrate can be supplied as a web in a roll.
It is also useful if a lighting device is compatible with existing lighting infrastructure, for example the common screw-type base (standard E26) and the pin-type bayonet base (standard B22). Moreover, the lighting devices are preferably readily and safely replaced by consumers at minimal cost.
There is a need therefore for an improved, replaceable OLED area illumination device having a simple construction using a single substrate, is compatible with the existing lighting infrastructure and can be provided in a variety of two and three-dimensional shapes.
The need is met by providing a solid-state area illumination light source that includes a rigid support; a flexible substrate attached to the rigid support; an organic light emitting diode (OLED) layer deposited on the flexible substrate, the organic light emitting diode layer including first and second electrodes for providing electrical power to the OLED layer, an encapsulating cover covering the OLED layer; first and second conductors electrically connected to the first and second electrodes, and extending beyond the encapsulating cover for making electrical contact to the first and second electrodes by an external power source; and a base connected to the rigid support, the base being adapted to be removably received by a socket and having first electrical contacts for making electrical connection to the first and second conductors of the light source, and second electrical contacts for making electrical connection to conductors in the socket.
The present invention has the advantage of providing an OLED light source that can be shipped and stored in a convenient flat configuration and deployed and used in a variety of three dimensional configurations.